1. We'll start with the most famous resident of your digestive tract, Escherichia coli, or E. coli for short. Until recently, E. coli was believed to be totally harmless, but in the 1980s some virulent strains appeared. One particularly nasty strain, called E. coli 0157:H7 has probably killed 200 people in Canada and the U.S. From what animal did this bizarre strain of E. coli arise? pigs horses chickens cattle

2. This incredibly hard-working bacteria, Lactobacillus acidophilus, produces lactase, which helps us digest milk and milk products. In addition, what other ways does it benefit our health? reduces cholesterol helps prevent yeast overgrowth all of these produces B-vitamins and K-vitamin

3. We're not done with Lactobacillus yet. Besides L. acidophilus, which other Lactobacillus is common in your gut, especially if you eat a lot of yoghurt? L. casei L. helveticus L. brevis L. bulgaricus

4. With regards to respiration, most intestinal flora are: aerotolerant (don't use oxygen but can survive it) obligatory anaerobes (cannot survive exposure to oxygen) facultative anaerobes(can use oxygen, but can also live without it) aerobes (need oxygen)

5. Because of the beneficial nature of intestinal bacteria like the Lactobacilli, many health-food stores now sell cultures of "probiotic" bacteria in pill form. Besides Lactobacillus, what other bacterial genus is most often represented in these cultures? Yersinia Mycoplasma Treponema Bifidobacterium

6. Although it's obvious that I'm a big fan of helpful bacteria, I wouldn't necessarily advise you to rush out and buy those probiotic cultures. What is the main reason to proceed with caution? probiotics might be a big waste of money probiotics are often carcinogenic probiotics have been known to cause endometriosis probiotic cultures are often contaminated

7. We've talked a lot about the helpful bacteria in your guts, but here's one that really doesn't do much for you, and in fact is sometimes harmful. Given the fact that it's named after a famous British surgeon who advocated antiseptics, what is it called? Millisia Wollbachia Listeria Klebsiella

8. Candida albicans, another common resident of your intestine and other areas, is a type of what? yeast bacteria mold virus

9. Clostridium is one of the deadliest genera of bacteria. Some species in this genus are responsible for botulism, gas gangrene, and tetatus. There's no such thing as a completely harmless Clostridium, but which *relatively* harmless species often lives in our gut without any serious effects? C. perfringens C. tetani C. difficile C. botulinium

10. If you are suffering from Clostridium overgrowth, or various other nasty enterobacteria like Salmonella or Vibrio, most antibiotics won't save you, but this yeast that grows on lychee nuts just might. (This being the last question, I'll give you two hints: it's the same genus as the yeast that brews beer, and it loves sugar!) Saccharomyces Torulaspora Pichia Nakaseomyces